This is technically true, however, in many cases the government has already waived immunity through past legislation, or a court has already found that immunity doesn't apply to particular cases due to for example constitutional reasons. Crucially, it's not like everyone who sues the government has to beg a judge every time before filing the suit.

See: https://en.wikipedia.org/wiki/Sovereign_immunity_in_the_Unit....

Aren't things like being offered an attorney and being informed of your charges legal requirements for detention in USA. What grounds would the state have to refuse a court case based on such things?

I'm hoping they'll get a massive payout and use some of it to launch a case against the authorities who allow such injustice to go unchecked.

Sovereign immunity only applies to the individuals that work for the state while executing their job. You can absolutely sue the state, federal agencies, or your town hall. They get sued all the time.

Derek Chauvin is getting the dogshit sued out of him now because he exceeded his duty and no longer qualified under sovereign immunity.